Risk-Based Approach for Defining Retest Dates for Active Pharmaceutical Ingredients and Excipients

Area of Science:

• Pharmaceutical Sciences
• Regulatory Affairs
• Quality Control

Background:

• Drug substances and excipients require adherence to storage conditions and specifications throughout their lifecycle.
• International Council for Harmonization (ICH) and World Health Organization (WHO) guidelines mandate retesting of drug substances post-retest period before use in manufacturing.
• The term "used immediately" following retesting presents an interpretational ambiguity in current regulatory practices.

Purpose of the Study:

• To elucidate the processes involved in determining the retest date for drug substances.
• To introduce a risk-based methodology for establishing retest dates.
• To define the acceptable timeframe for the utilization of drug substances after retesting.

Main Methods:

• Review of existing regulatory guidelines (ICH, WHO) concerning drug substance retesting.
• Analysis of the "used immediately" clause and its implications.
• Development and presentation of a risk-based framework for retest date determination and material usage.

Main Results:

• Identification of key processes and considerations for establishing drug substance retest dates.
• A proposed risk-based approach to manage retest dating and material usability.
• Clarification of the ambiguity surrounding the immediate use of retested drug substances.

Conclusions:

• Establishing accurate retest dates is critical for ensuring drug product quality and regulatory compliance.
• A risk-based strategy can provide a more defined and scientifically sound approach to managing drug substance usability.
• Clearer interpretation and application of retest period guidelines are necessary for pharmaceutical manufacturing.